Structure and Cooperativity of the Cytosolic Domain of the CorA Mg2+ Channel from Escherichia coli.
Structure
; 25(8): 1175-1186.e4, 2017 08 01.
Article
em En
| MEDLINE
| ID: mdl-28669631
ABSTRACT
Structures of the Mg2+ bound (closed) and apo (open) states of CorA suggests that channel gating is accomplished by rigid-body motions between symmetric and asymmetric assemblies of the cytosolic portions of the five subunits in response to ligand (Mg2+) binding/unbinding at interfacial sites. Here, we structurally and biochemically characterize the isolated cytosolic domain from Escherichia coli CorA. The data reveal an Mg2+-ligand binding site located in a novel position between each of the five subunits and two Mg2+ ions trapped inside the pore. Soaking experiments show that cobalt hexammine outcompetes Mg2+ at the pore site closest to the membrane. This represents the first structural information of how an analog of hexa-hydrated Mg2+ (and competitive inhibitor of CorA) associates to the CorA pore. Biochemical data on the isolated cytoplasmic domain and full-length protein suggests that gating of the CorA channel is governed cooperatively.
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Base de dados:
MEDLINE
Assunto principal:
Ativação do Canal Iônico
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Proteínas de Escherichia coli
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Proteínas de Transporte de Cátions
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Magnésio
Idioma:
En
Ano de publicação:
2017
Tipo de documento:
Article